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Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to optimize the mechanized production equipment of flax seeds by means of discrete element method to provide the basic parameters of flax seeds, the basic physical parameters and partial contact mechanical parameters of flax seeds were determined by the experimental method for 3 kinds of flax seeds, Dingya 22, Longya 10 and Longya 13, which are widely planted in Gansu Province of China. The basic physical parameters include three directions of size, mass density, bulk density, Poisson's ratio, 1,000-kernel weight, seed moisture content, and elastic modulus of flax seeds. Three kinds of flax seeds were randomly selected from 500 flax seeds, and the triaxial size of the flax was measured by Vernier calipers. The statistical results showed that the long average of Dingya 22 was 4.83 mm, the width was 2.39 mm, and the thickness was 0.85 mm. The average length was 4.43 mm, the width was 2.38 mm, and the thickness was 0.95 mm. The average length of Longya 13 was 5.13 mm, the width was 2.47 mm, and the thickness was 1.02 mm. The volume of the flax seed was calculated by the 3-axis size. Distribution of 3-dimensional volume of 3 kinds of flax seeds were basically normal distribution. With the pressure deformation experiment of flax seeds was carried out by electric double column tension test bench, and the Poisson's ratio was calculated by measuring the deformation amount of width and thickness before and after loading flax seeds, and Poisson's ratio of flax seed was 0.403, 0.410 and 0.409, respectively. The coefficient of static friction of flax seed was measured by the bevel method, and the coefficient of static friction between flax seeds were 0.240, 0.201 and 0.204, respectively. The collision recovery coefficient between flax seeds was determined by free fall experiment, and the collision recovery coefficient was 0.433, 0.389, 0.430, respectively. The elastic modulus of the load-displacement curve of the flax seeds obtained by the flax pressure experiment was 370.16, 558.28, 370.18 MPa. By the simulation repose angle of flax models under the different coefficient of rolling friction of flax seeds that were put to the actual repose angle of flax seeds, the coefficient of rolling friction of flax seeds was predicted, and the result was that the coefficient of rolling friction of flax seeds was 0.0410, 0.0425 and 0.0420 for Dingya 22, Longya 10, and Longya 13, respectively. The influence of the coefficient of rolling friction on the repose process of flax seeds was analyzed. With the decrease of the coefficient of rolling friction, the contact quantity of flax seeds and bottom plate increased. The rotational kinetic energy of flax seed population increased first, and then decreased during the accumulation process. At the same time point, the coefficient of rolling friction of flax seeds decreased and the rotational kinetic energy increased. Based on the calibration parameters of flax seeds, the arrangement of heterosexous hole seeding device with flax seeds was carried out. The simulation results showed that the number of granules was 8-11, the average number of granules was 9.5, and the standard deviation was 0.5. Through the field trial experiment of flax combined planter, the number of seeds in the hole of the 81 hole in the collection area was counted. The results showed that the number of seeds in the first, second and third rows of seedlings fluctuated between 8 and 12, with an average of 9, standard deviation of 1. The average value of the simulated and experimental granules was 0.5, and the relative error was 5.26%. The flax seeds were small, and the number of leaks in the process of flax mining statistics occurred, resulting in certain errors in the experiment and simulation results. The flax simulation parameters calibrated in this paper have certain significance in guiding optimizing the seeding working parameters of the flax seeder. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to solve simulation distortion problems of soil resistance and dynamic movement with discrete element method, the hysteretic spring contact model (HSCM) and the liner cohesion model (LCM) were used to simulate farmland soils in order to investigate their soil plasticity behavior and dynamics, which could be used for predicting the resistance of farm tools. To achieve better simulation results, soil basic physical parameters, contact mechanical parameters and contact model parameters of HSCM and LCM were needed. Soil basic physical parameters included particle size distribution, soil particle density, elasticity modulus, shear modulus, poisson's ratio and bulk density. Among them, the elasticity modulus was obtained by the related literature. Soil contact mechanical parameters included cohesion between soil particles formed due to the action of the water liquid bridge, cohesive strength and internal friction angle obtained from soil shear test with 6 kinds of different soil moisture. Contact model parameters were composed of coefficient of restitution, static friction coefficient and dynamic friction coefficient. The soil particles were 5 mm so that the simulation time could be shortened. Because soil simulation particles were larger than actual ones, additionally in order to achieve better simulation results, a simulation model of soil contact parameter prediction model was established according to central experimental design method (Box-Behnken) used for a comprehensive analysis of fewer trial times. Taking static friction coefficient, dynamic friction coefficient and shear strength as test factors, and soil accumulation angle as response value, 17 sets of simulation tests were carried out according to response surface method test arrangement. The results showed that the influence of static friction coefficient, dynamic friction coefficient and the interaction between dynamic friction coefficient and cohesion strength on repose angle were significant. Interaction between static friction coefficient and dynamic friction coefficient, quadratic term of static friction coefficient had a significant effect on repose angle. Taking repose angle of soil with moisture of 1%, 4%, 8%, 12%, 16% and 20% as the response value, fixing the cohesion strength, we predicted the static friction coefficient and dynamic friction coefficient using the established regression model. Then, the results were validated by soil shear test. The results showed that the relative error of shear strength was 1.18%-9.31%, and the relative error of internal friction angle was 0.55%-4.07%. In order to verify the feasibility of the proposed soil contact model, a test by using duckbill opening hole test device in soil was carried out and the results showed that when the displacement was 0-50 mm the deviation of simulation and test was big. But when the displacemtn was 50 mm, the relative error was 0.928%, which could be used for design of duckbill structure in the future. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In solving The problem on the seed com mechanization sowing in the northwest area and understanding the com sowing conditions and agronomic requirements, an electric driving com hill-drop planter with inserting on film in the plot was developed. The differential motor drives are installed in the front wheel shaft with the front wheel moving ahead. Also, the motor drives are used for the electromagnetic clutch to rotate. Whenever the clutch is switched on. the input power of the motor crank shaft sprocket is used through a different number of the teeth of the deceleration after the transfer to increase the speed compensation mechanism. The uniform rotation of the input crank guide rod achieves a non-uniform rotation that drives the non-uniform rotary motion of the parallel four-bar mechanism, which means that when the planter moves forward, the duckbill in the sowing period goes straight up and down relative to the ground. The sowing device assembly makes the toggle wheel move by the up and down movement of the brace, driving the wheel wrench to turn to take or discharge seeds, and to pull the trigger on the active duckbill to achieve the seed discharging. The sowing device components are attached to the sowing rod through the slider and spring damper. When the hard ground or rock spring damper is compressed, it protects the duckbill. When there is a leakage sowing, the sowing alarm installed on metering device will alarm the module to remind the artificial sowing. As part of the core components of the forward speed compensation mechanism, the depth limiting and rear-wheel height adjusting mechanisms were designed and simulated. The forward speed compensation mechanism consists mainly of crank rod. slider, guide rod. driving rod. driven rod. and bunch rod. The core function of attaining the forward speed compensation under the periodically rotating guide bar drives the parallel four-bar mechanism. Compensation under the buried and unearthed planting bars, which is near zero speed, promotes the corn growth around the bed (deficient in the upper bed and excess in the lower bed), makes the com less damaged, and reduces the planting bar to tear the plastic film. Considering the tread of the front wheel of the planters is small, the seed sowing performance and the pass rate of sowing depth for the seed sowing device are affected by the ground roughness. Also, the com seeds germinate better under the same sowing depth. With this, the depth limiting mechanism was designed. In meeting the demand of the film mulching and ridge tillage, the walking machine maintains the level, and when there is no operation the duckbill of the planter avoids touching the surface and tearing film, and the rear height adjusting mechanism designed is mainly composed of push rod. DC (direct current) linear electric push rod. rotating shaft, bottom bar and land wheel. In the perform test, the results showed that the hole rate was 1.1%. the qualified rate of seeds number per cavity was 93.2%. and the pass rate of sowing depth under the film was 90.1%. The three sowing core indicators have reached the standard of NY/T 987-2006 PU film dibbling machine operation quality, and the film hole qualified rate was 98.5%. The test results show the operation of compensation device is stable and reliable in the forward speed, which was placed on the 2 lines of symmetry and greatly reduced the vibration of the whole machine cycle. The film holes of the duckbill inserted were smaller, and hole and film hole have not slipped, and the qualified rate of sowing depth was higher. After encountering stones, the duckbill will not insert into it forcedly. The results of this study met the design and agronomic requirements as cited. [ABSTRACT FROM AUTHOR]